[Determination of trace lead in environmental water by cloud point extraction-high resolution continuum source graphite furnace atomic absorption spectrometry].

Comparison investigations were performed for the enrichment method of lead in environmental waters, including coprecipitation, ion exchange and cloud point extraction (CPE). CPE was selected as the optimal enrichment method because of its less consumption of water sample, higher enrichment factor and simpler procedure than the other enrichment methods. Pb contents in the water samples from Tonghui River in Beijing were determined by high resolution continuum source graphite furnace atomic absorption spectrometry coupled with CPE enrichment. The results indicate that the limit of detection of the method is 0.08 microg x L(-1), the relative standard deviation (RSD) is 1.3% to 4.5% (n = 6), the recovery of Pb contents is 93% to 108%, and the enrichment factor of CPE method is 29. The Pb contents in the 13 water samples from Tonghui River all conform to the Environmental Quality Standards for Surface Water (Grade I). Moreover, the Pb content in the whole river exhibits a decreasing trend from Tongzhou district to Chaoyang district.